Grease is added to the gear box or the transmission shaft for most of the heavy duty tools or vehicles so as to lubricate the gears and bearings and movable parts to reduce friction. The adding of the grease is made by using a grease gun 9 which is disclosed in FIG. 9. The grease stored in the grease can 92 is injected to the gear box or the transmission shaft via the outlet 93 of the body 91 of the gun 9.
The conventional pneumatic grease gun 9 is operated in single shot each time so that when a large amount of grease is needed, the user has to repeatedly pull the trigger 94, and this is not convenient. TW-M279793 discloses a grease gun which provides a large amount of grease by one operation of the trigger to improve the shortcoming of the conventional pneumatic grease gun.
However, when operating the grease gun that supplies a large amount of grease within one shot, the amount of the grease may be much more than needed. This becomes waste of the grease.
The present invention intends to provide a grease gun with an auto/single functions selecting device which allows the user to choose desired function to get the desired amount of grease.